Composition for brake-band linings.



MARY-M. HOLDEN, or NEW YORK, N. Y.

COMPOSITION FOR BRAKE-BANDLININGS.

No Drawing.

To all whom it may concern:

Be it known that I, MARY M. HOLDEN, a citizen of the United States,residing at the city of New York, in the borough of Brooklyn and Stateof New York, have invented certain new and useful Improvements inComposition for Brake-Band Linings, of which the following is a full,clear, and exact description.

This invention relates to a composition which is adapted for use as alining for brake bands, brake shoes and the like.

One object of the invention is to provide a composition which, when usedas a lining for brake bands, will permit a slight slippage between themember to be braked and the braking member when the brake is'firstapplied and so cause a stoppage of the member to be braked without anysudden shocks or jars.

Another object of the invention is to provide a composition which issofter than the brake drum or the like and yet possesses the requisitecoherency between its particles to render unnecessary'anyreinforcements, such as wire mesh or the like, to hold it together.

Another object is to provide a composition for this purpose which willhave a relatively high melting point. i

Other objects and advantages -of my invention will appear from thefollowing description.

The invention consists in a composition of the/character described, theessential constituents of which are copper and lead, the lead being in agreater percentage than cop per. Preferably, substantially three partscopper and five part-s lead are used. Lead is particularly suitable as acomponent of a brake band lining when combined with a stronger metal forthe reason that its properties and characteristics are such that it willpermita slight slippage between the lining and the braking member whenthe brake band or the like is frictionally applied. A small percentageof phosphorus in the form of phosphor copper may be added to thecomposition to give it additional toughness and hardness.

As is well known, copper in forming an alloy with lead will not take upmore than approximately one-half of one'per cent. of

lead and form with it a true alloy. It is also I well known that informing a lead-copper alloy, lead will not take up more thanapproximately one-half of one per cent. of

Specification of Letters Patent.

Patented Oct. 31, 1916.

I Application filed April 22, 1916. SerialNo. 92,966.

copper. The small quantities of lead and copper which are thus taken uphave no material effect upon the characteristics of these two metals andthe composition may therefore be regarded as a mechanical mixture of thetwo. 'In the mixture, the copper blends or amalgamates with the lead,making the mixture homogeneous throughout. When the composition istherefore cast into bars and utilized as a lining-for a brake band, shoeor other form of brake, the lead present in the contacting surface ofthe lining permits a slight slippage of the brake drum or other memberto be braked when the brake band is first applied under a relativelyslight pressure. This slippageis not, however, suflicient to prevent apositive braking action frombeing obtained, since the copper in thecomposition not only prevents any deformatioirin the lining due to theflow of Copper 36 per cent., lead 62% per cent., sulfur one half percent., plaster of Paris-onehalf per cent., phosphor copper one-halfpercent., and with these constituents the composition is prepared asfollows: The copper is first melted in a suitable vessel and the lead isthen added. Since the melting point of lead is so much lower than thecopper, the lead may be added to the molten copper in solid form andwill .be quickly melted. The lead and copper are then stirred togetherin order to form as intimate a mixture of the two metals as possible.The copper will then take up a very small percentage of the lead; thatis, about one half of one per cent. and forms with it' or gypsum arethen added to purify the metal. The sulfur reduces an metallic oxids ofthe metals which may epresent in small quantities, acting as a reducingagent and converting any of the oxids of lead or copper to metalliccopper and lead and giving off S0,. 'The plaster of Paris cleanses themolten-mass of metal of other impurities, such as silica, and the like,which I forms a thin liquid slag-upon the top of the mass of metalwithin the vessel, which may be skimmed oil before casting. After thecopper and lead have been purified, phosphorus is added, preferably inthe form of phosphor copper which as before stated, tends to toughen thecomposition. The mixture, before casting, is preferably violentlyagitated or otherwise treated so as to cause an intimate mixture ofthecopperand the lead, producing a uniformly blended composition. 7

It is believed that the homogeneous mixture of the copper and lead'isobtained because of the sulfur which is added to the molten mass, sinceit has been found that without the addition of this sulfur it is Verydifiicult, if not impossible, to obtain an intimate mixture of the leadand copper, which will not separate out before the metal cools.

The composition is in the'usual manner cast in bars or in hollow brakeshoes so as to form fillers for the same. lVhen cast in bars, it ispreferably attached to the brake band or shoe by means of soft copperscrews so thatthe heads of the screws will be worn uniformly with thebrake band and will not scratch or injure the face of the brake drum orpulley.

I claim:

1. A metallic lining .for brake bands and the like containing copper andlead in excess of the copper, the c'opper content being greater thanthat which will form a true alloy with the lead,

2. A metallic lining for brake bands and the like containing copper andlead in substantially the proportion of three parts copper to five partslead.

3. A metallic lining for brake bands and the like containingsubstantially ,five part-s lead, three parts copper and a smallpercentage of a phosphorous alloy.

4. The for linings for brake bands cons sting in first melting aquantity of copper, then adding substantially a larger amount of leadthereto and permitting it to melt, then adding a small percentage ofphosphorous alloy, then adding a small percentage of sulfur and plasterof Paris, then skimming the mixture and thoroughly mixing theingredients as it is allowed to cool.

5. The process of preparing a composition for linings for brake bands,which comprises mixing molten copper, lead and sulfur together,agitating the molten mass and then casting.

, 6. The process of preparing a composition for linings for brake bands,which comprises mixing molten copper, lead, sulfur, gypsum andphosphorus, then stirring the molten mass, and casting. I

In witness whereof, I subscribe my signature, in the presence of twowitnesses.

MARY HOLDEN.

process of preparing a composition

